Hole cutter



Sept. 15, 1931. E. c. swANsoN 1,823,218

HOLE CUTTER Filed nan-.h 1, 1929 Patented Slept. 15, 1.931'

unirse STATESv PATENT OFFICE- EDWIN C. SWANSON, OFKROCKORD, ILLINOIS, ASSIGNOR TO GREENLEE BROS. & CO., f Y ROCKFORD, ILLINOIS, A CORPORATION OF ILLINOIS (Horn CUTTER Application mea March 1,

This invention relates to cutters for makingjcircular holes in sheet metal particularly adapted for use in making or enlarging holes in fuse boxes, junction boxes, switch boxes and the like. 1 In the installation of conduit for electrical equipment and wiring it is customary to inf sert metal boxes at appropriate points in the systemsuch as fuse boxes, switch boxes, starting boxes and the like. These boxes are usually purchased ready-made and in many cases are provided with a number of knockouts or potential openings for attaching the conduit, formed by only :partially cutting through the metal leaving the blank therein, the appropriate one to be removed yby a sharp blowf'from a hammer or other'tool at the time of installation. iW'hile these knockouts serve the purpose admirably when conduit of the normal size is used, they must, of course, be enlarged or newy openings cut to accommodate larger conduit. This has, in the past, been accomplished in most cases byldrilling small holes on the periphery of the circle desired to be cut and sawing the metal therebetweenv with a hacksaw. OtherV equipment forvthis purpose has been provided, however, such as toolswhich cut by removing thev metal, circularband saws, and .so stamping dies.:

rThoseage'ncies which act by removing the metal, whileperhaps lthe most popular, are farvv from satisfactory, for whenthe metal has been removed until but a thin layer remains 3i the tool has a tendency to dive through the layer taking too large a ,bite and either breaking or freezing ythe tool. Circular band saws have'a tendency to freeze and turn hard because of the small clearance between the sides of the cut and the distortion of the saw. Stamping dies require too much power to be of .portable use excepton' the very lightest'metal.

`My invention contemplates the provision of a series of circular discs of varying sizes any one of which may be `held against the metal by means of a bolt passing through the center. A rotatable bar is mounted on the bolt yon the oppositelside -of the metal Vand is equipped with sharp edged wheels 1929. serial No. 343,592.

which, when the bar is turned, inscribe a circle corresponding to the periphery of the disc beneath. Pressure is applied between the disc and the wheels to progressively sheer the metal.

One ofthe objects of my invention is the provision of means for cutting circular holes in sheet metal progressively and with comparative ease.

I have also aimed to provide a cutter relatively light in weight and small in size to permit its use in cramped or limited quarters, and adapted to cut holes of a number of different sizes.

Still' other objects of the invention will be `apparent to those skilled in this art from the following description and accompanying drawings-in which: Figure l is a side elevation of the hole cutter in a position for operation showin a sheet oflmetalbetween a disc body and the cutter wheels; o Fig. Q is a top view of the cutter equippedk with the disc body shown in Fig. 1f;

Fig. is a section on the line 3 3y of Fig. 2 showing cutter in usey with a disc body gio similar to that shown in Fig. l, but of different size; and

Fig. l is asection on the line 4.--4 of Fig. 3 showing the supporting wedge in position.

The machine consists essentially in a supporting bolt upon which is mounted a disc, a cutter arm carrying cutter wheels projecting downward at the periphery of the disc, the metal being cut between the two by rotating'the cutter arm and simultaneously applying pressure through suitable means such as a nut at the end of the bolt. The discs are adapted to be changed for others of different diameters and the cutter wheels are capable of beingchanged to correspond therewith.

-A bolt 6, best shown in Fig. 3 has a wide flat head 7 adapted to support a disc body designated generally by 8. A key 9 in the bolt cooperates with a slot l0 in the disc and prevents the bolt from turning therein. i The disc 8 is circular in shapeand provided with Vparallel sides l1 and l2 of diiferent radii, the .side l1 being adapted to rest against the metal when the smaller hole is being cut and to allow for grinding. A plurality of theseA discbodies having faces of varying radius may be employed to permit the machine to be used to cut holes of varying sizes. I haveV`V shown two disk bodies adapted for use in cutting holes of four different sizes, the larger discV being shown in Figs.k *1 and 2 (having reference numerals 11, 12', 13 and 14'.) and the smaller in 3. The supporting bolt with the disc attached is designed to be inserted through a small holein the stockerr metal to be cut which may be made therein with a drill of the ordinary type. Where metal boxes provided with knock-outs are being used one of these may be removed to act as an opening for the bolt. A cutter arm 15 is rotatably mounted on the supporting bolt at its center; A nut shaped portion 16 is fixedly'attached to the cutter arm by means of a flange 17 and pin 18, and extends upward around the supporting bolt v6 providing a means for turning the` cutter bar abo-ut said bolt with a wrench.` The bar has recessed portions 19 near each end thereof which form the lower part of the bar into a central hub or bearing portion 20 and end flanges 21 and serve to receive the cutting mechanism. Bearing pin 22 passing through the recesses fit closely at. one end into holes 23 in the hubportion and are threaded at the other end intoV the flanged ends at 24. The heads of the pins are provid-ed with slots whereby the pins 'are easily lremoved with a screw driver. yBushings 25 surround the pins i. through the entire length of the recesses and have flanges 26 at one end to actas spacing members. Mounted upon the bushings are the spacing blocks 27 and the cutter wheels 28. The spacing blocks, in this case of triangularY form shown in outline in Fig. 4, are

twoin number on each bushing and serve to permit the cutter lwheel to be moved to dif? ferent'positions along the bushing. They also serve..because of their flat upper edges.

29, Vwhichrest firmly against the cutter arm, to support the pins and bushings against the upward thrust on the cutter wheels when the latter are being forced into the metal. The Y The disc 8 and thecutter wheels'are drawn Y together'against the metal by'means of a nut 32 threaded on the upper end of the bolt 6. The threads are out to advance the nut slowly and thus give a close regulation of the cutting speed and power required for turning the cutter arm. interposed between the nut like portion 16 of the cutter arm and the nut 32 isa. lock washer 33 having a projection 34 extending into a slot 35 of the bolt 16 to prevent the turning movement of the cutter bar from being transmitted tothe nut 32 and disturbing its setting.V

The operation of my improved cutter will be seen to vbe at once effective andk simple. The operator first provides a small opening large enough for the bolt 6in the metal by means of a drill or'otherwise. The supporting boltfwith'the proper sized disc 8 thereon is inserted in the opening. The cutter wheels are set on the pin 22 vin a position tocooperate in a self evident manner with the disc chosen. This may be done by interchanging the cutter wheels with either of the spacingblccks or by reversing the bushings 25 to place the flanges at the opposite side of the recesses. The cutterbar' with the cutter wheels prop erlyV placed is slipped over the bolt` 6 on the opposite side of the metal from the disc. The lock washer 33 is placed upon the bolt and the nut 32 screwed thereon. The nut is drawn tight and the cutter bar turned by means of a wrench applied to the nut-like portion 16. The nut 32 is intermittently drawn up as the cutter wheels maketheir wayv through the metal and release the pressure.'v

My cutter w-ill be seen to offer a number of distinct advantages. The speed at which the metal is Vcut and consequently theforce required to. turn the v'arm maybe regulated at will. A number of different sizes of' holes may be cut with the same cutter; The stock is not bent but progressively sheered through between the cutter wheels and the peripheral ating space is narrow. The device is sturdy,

not easily broken, and long lived.

While I have shown and described 'a parn ticular embodiment of my invention for purposes of illustration l am aware that numerous changes and modifications maybe made without departingfroi'n the spirit and scope of the Vinvention as described and claimed. l

l claim: Y Y Y '.1. AV circle cutter comprising a circular disc, supporting means at the center thereof adapted to pass through al hole in the stock and support the disc closely thereto, a cutter arm `rotatably mounted upon said' supporting means on the opposite side of the stock. from said disc, cutter wheels rotatably mounted on the cutter arm and projecting from the b0ttom side thereof in a positionv to inscribe a circle of the same diameter as the disc below,

and means for applying pressure between the cutter arm and the circular disc. 2. A circle cutter of the character described having a disc body each end of which is of a diameter different from the other and adapted to be seated in operative position against one side of a. metal sheet to be cut, and cutting wheels adapted to bear against the opposite side of the metal sheet opposite the periphery of either end of said disc body to cooperate therewith in shearing the metal.

3. A circular cutter comprising a circular disc each end of which presents a Hat circular face of a diameter different from the other adapted to rest in an operative position against one side of a metal sheet to be out, a plurality of cutting wheels adapted to bear against the opposite side of the metal sheet opposite the periphery of the disc in operative position to cooperate therewith in shearing the metal, means for rotatably supporting said cutting wheels and permitting adjustment thereof to cooperate with either disc diameter, and independently operable means for applying pressure between said wheels and said disc to cut the interposed metal sheet.

4. A circle cutter of the character described having cutters, a rotatable cutter carrying part adapted to be positioned at one side of a metal sheet tovbe cut, a center bolt adapted to pass through the metal sheet and to provide bearing support for said cuttercarrying part on which the latter turns, and a disc body mounted on said center bolt at the side of the metal sheet opposite from said cutter-carrying part, said disc body having fiat circular ends each of different diameter from the other and adapted to seat in an operative position against the metal sheet and determining `the diameter of the hole to be cut, the cutters being adjustable to the diameter of the hole to be cut as determined by the disc end in operative position, and means `for manually applying pressure, independent of said cutter carryingv part, between the cutter-carrying part and the disc to cut the interposed metal sheet.

5. A circle cutter having a central bolt adaptedto be located in a'hole in a metal sheet, a disc secured on'said bolt at one side of the metal sheet, a cutter arm rotatable upon said bolt at the opposite side of the metal sheet equipped with cutting wheels for cutting the interposed sheet, means for applying pressure between said disk andsaid cutter arm to effect the cutting,l each cutting wheel being mounted to rotate on an elongated bearing on the cutter arm radial with respect to the center bolt, and interchangeable bearingl blocks on 'the said bearings i adapted to hold the cutting wheels in loca- 6. A circular cutter as set forth in claim 5, in which the bearing blocks have thrust contact against the cutter arm to take the thrust f from the cutter.

7. A circular cutter as set forth in claim 5,

in which each cutting Wheel and one or more ing adjustable to eiect diiferent diameters of cuts.

9. A circle cutter comprising a center bolt adapted to be located in an opening in a metal sheet to be cut, means adapted to be non-rotatably mounted on the bolt at one side of the metal sheet having a plurality of cutting edges, any one of which may be placed in operative position thereagainst, a cutter arm adapted to be positioned on the bolt at the opposite side of the metal sheet equipped with cutting means complemental to said cutting edges and adapted to be rotated about the center bolt, and means operative between the center bolt and the cutter arm to apply pressure between the cutting means and said first mentioned means to effect cutting of the metal when the cutter arm is rotated.

10. A circle cutter comprising meansI having a plurality of cutting edges of different diameters for selective transposition next to the sheet to be cut, a supporting bolt passing through the center thereof and attached thereto adapted'to pass through a hole in the stock to be cut, a cutter arm rotatably mounted upon said supporting bolt on the opposite side of the stock from said means having recessed portions therein, bearing pins passing through said recessed portions and seated at either end in said arm, a cutter wheel and a plurality of spacing blocks mounted upon each of said bearing pins adapted to be interchanged in position to move the cutter wheel in and out upon the pin to cooperate with said cuttingedges, and a nut threaded on said supporting bolt to be turned downward in bringing the cutter wheels and said means together and to bring a desired pressure upon the metal therebetween.

l1. A circle cutter comprising means having a plurality of cutting edges of different diameters for selective transposition next to he sheet to be out, a supporting bolt passing through the center thereof and attached thereto adapted to pass through a hole in the stock to be cut, a cutter arm rotatably mounted upon said supporting bolt on the opposite side of the stock from said means and having recessed portions therein, bearing .pins passing through said recessed portions and seated at either end in said arm, bushings on said pins, cutter wheels rotatably mounted upon said bushings and projectingfrom the bottom side of said cutter arm in a position to inscribe a circle of the same diameter as the cutting edge next to the metal, spacing blocks mounted on said bushings adapted to supf port the bushings and hold the cutter wheel in its rotatable position While permitting the same to be moved in conjunction with the v cutting edges to cut diierent sizes of holes,

and a nut threaded yon said supporting bolt adapted to be turned downward to bring said means and cutter wheels closer together and place a desired pressure therebetween.

12. ln a circle cutter a cutter armcomprising a bar having a central pivotal opening, recessed portions near each end and a central projecting portion for cooperation with a wrench or other tool in turning the Y arm, bearingV pins passing horizontally through each of said recessed portions and seated at either end in said arm, bushings i having an annular projecting portion at one end mounted upon said bearing pins, a cutter wheel, and a plurality of spacing blocks mounted upon said bearing pin and bushing in each recess, said blocks being adapted to cooperate with the cutter arm surface to support the bushing and bearing pin and to be interchangeable with said cutter wheel permitting the latter to beused in a series of diferent positions in cutting holes of dif- Vferent sizes.

13. A circle cutter comprising a cent-er bolt adapted to'be located in an opening in a metal sheet to be cut, a cutter disc adaptedto be non-rotatabiy mounted on the bolt at one side of the Inetalk sheet, a cut-ter arm adapted Y to be positioned on the bolt atV the opposite side of the metal sheet equipped with cutting means complemental to the cutterdisc and adapted to be rotated aboutt-he center bolt, means operable between the center bolt and the cutter arm to apply pressure between the cutting means and the cutter disc to effect cutting of the metal when the cutter arm is rotated, and means for preventing rotation of the cutter arm from being transmitted to the last mentioned means. Y

e In witness of the foregoing I aiiiX my signature. Y l

` EDVVN C. SVANSON. 

